Spanner bars and other secondary support structures are commonly used in commercial aircraft for wire bundle management. The spanner bars may be secured to system support brackets, which are attached to primary aircraft structure. Wire support hardware such as p-clamps and ring posts are fastened to the spanner bars. Wire bundles are secured to the wire support hardware.
Wire support hardware may be attached to a spanner bar as follows. The wire support hardware is positioned on a front side of the spanner bar. The threaded portion of a fastener is aligned with a select open hole of the spanner bar and an open hole of the wire support hardware. The fastener is maneuvered through the holes until the threaded portion is exposed on a back side of the spanner bar. A loose washer and nut are placed over the threaded portion, and the nut is tightened with a hand tool until firmly clamped against the spanner bar. This process is repeated for each fastener.
Often, there is no visual sightline to the back side of the spanner bar. Therefore, the nut and washer are installed blindly. Some manual dexterity is needed to install the nut and washer blindly without dropping either part.
It would be desirable to reduce part count and installation time of attaching wire support hardware to a spanner bar. Even a seemingly trivial reduction for a single nut and washer can be significant due to the large number of fastening operations on secondary support structures in a commercial aircraft.